Method and apparatus for delivering defibrillation shock therapy while reducing electrical dispersion due to ventricular conduction disorder

Abstract

A method and device for delivering defibrillation shock therapy in patients having an inter-ventricular conduction disorder is presented. Ventricular resynchronization therapy is employed to reduce the dispersion of ventricular depolarization which takes place due to the conduction disorder and reduces the safety margin of shocks delivered synchronously with ventricular beats. The method may be employed in the treatment of atrial or ventricular tachyarrhythmias.

1. A method for delivering ventricular cardioversion therapy to a patient, comprising:
 identifying the patient as having a ventricular conduction deficit by measuring the patient's ventricular conduction delay; and, 
 configuring an implantable cardiac rhythm management device implanted in the patient to detect the presence of a ventricular tachyarrhythmia and, in response thereto, to: 
 initiate delivery of ventricular pacing in a selected pacing mode which reduces QRS dispersion from that exhibited by an intrinsic beat in the patient; and, 
 deliver a cardioversion shock after a predetermined time interval following a ventricular pace. 
 
     
     
       2. The method of  claim 1  wherein the ventricular pacing is a multi-site pacing mode. 
     
     
       3. The method of  claim 2  wherein the multi-site pacing mode includes pacing at least one right ventricular site and at least one left ventricular site. 
     
     
       4. The method of  claim 1  wherein the cardioversion shock is delivered synchronously with a sensed R wave if an R-R interval is longer than a specified minimum limit value. 
     
     
       5. The method of  claim 1  further comprising delivering a ventricular pacing pulse synchronously with the cardioversion shock. 
     
     
       6. The method of  claim 1  further comprising delivering a sequence of multiple ventricular paces before delivering a shock pulse. 
     
     
       7. The method of  claim 1  wherein the ventricular pacing is delivered in a left ventricle-only or biventricular pacing mode. 
     
     
       8. A method for delivering ventricular cardioversion therapy, comprising:
 detecting the presence of a ventricular tachyarrhythmia; 
 delivering a first type of ventricular pacing while no ventricular tachyarrhythmia is detected; 
 delivering a second type of ventricular pacing while a ventricular tachyarrhythmia is detected; 
 wherein the QRS dispersion resulting from the first type of ventricular pacing is greater than the QRS dispersion resulting from the second type of ventricular pacing; and, 
 delivering a cardioversion shock pulse within a predetermined time after a pacing pulse of the second type of ventricular pacing. 
 
     
     
       9. The method of  claim 8  wherein the first type of ventricular pacing is right ventricular pacing. 
     
     
       10. The method of  claim 8  wherein the second type of ventricular pacing is left ventricular pacing. 
     
     
       11. The method of  claim 8  wherein the second type of ventricular pacing is biventricular pacing. 
     
     
       12. A device for delivering ventricular cardioversion therapy, comprising:
 sensing circuitry for sensing cardiac electrical activity; 
 pulse generation circuitry for generating pacing pulses and shock pulses; 
 a controller for controlling the operation of the device; 
 a switching network operable by the controller for connecting the pulse generation circuitry and sensing circuitry to selected electrodes in order to configure selected sensing and pacing channels 
 wherein the controller is programmed to: 
 configure a sensing channel for detecting the presence of a ventricular tachyarrhythmia and configure sensing/pacing channels for delivering biventricular pacing therapy and sensing ventricular depolarizations (R waves); 
 initiate ventricular pacing in a mode which includes pacing of the left ventricle after detection of a tachyarrhythmia; 
 sense an R wave after a ventricular pace and measure an R-R interval; and, 
 deliver a cardioversion shock pulse synchronously with the sensed R wave if the R-R interval is longer than a specified minimum limit value. 
 
     
     
       13. The device of  claim 12  wherein the controller is programmed to deliver ventricular pacing in a multi-site pacing mode. 
     
     
       14. The device of  claim 13  wherein the multi-site pacing mode includes pacing at least one right ventricular site and at least one left ventricular site. 
     
     
       15. The device of  claim 12  wherein the controller is programmed to deliver a ventricular pacing pulse synchronously with the cardioversion shock. 
     
     
       16. The device of  claim 12  wherein controller is programmed to deliver the ventricular pacing in a left ventricle-only or biventricular pacing mode. 
     
     
       17. A device for delivering ventricular cardioversion therapy, comprising:
 sensing circuitry for sensing cardiac electrical activity; 
 pulse generation circuitry for generating pacing pulses and shock pulses; 
 a controller for controlling the operation of the device; 
 a switching network operable by the controller for connecting the pulse generation circuitry and sensing circuitry to selected electrodes in order to configure selected sensing and pacing channels 
 wherein the controller is programmed to: 
 configure a sensing channel for detecting the presence of a ventricular tachyarrhythmia and configure sensing/pacing channels for delivering a first and a second type of ventricular pacing, wherein QRS dispersion resulting from the first type of ventricular pacing is greater than QRS dispersion resulting from the second type of ventricular pacing; 
 deliver a first type of ventricular pacing while no ventricular tachyarrhythmia is detected; 
 deliver a second type of ventricular pacing while a ventricular tachyarrhythmia is detected; 
 and, 
 deliver a cardioversion shock pulse within a predetermined time after a pacing pulse of the second type of ventricular pacing. 
 
     
     
       18. The device of  claim 17  wherein the first type of ventricular pacing is right ventricular pacing. 
     
     
       19. The device of  claim 17  wherein the second type of ventricular pacing is left ventricular pacing. 
     
     
       20. The device of  claim 17  wherein the second type of ventricular pacing is biventricular pacing.